Manufacture of drawing tacks



March 9 1926.

G- LEIGHTON IANUFACTURE 0F DRAWI NG TAOKS' Filed March 4, 1922 Patented Mar. 9, 1926.

UNITED STATES.

GEORGES LEIGHTON, or rARrs, FRANCE.

I MANUFACTURE OFLDRAWING TACKS.

Application fi1ed-Ma1cl1-4, 1922. Serial No. 541,07. I

To all whom it may concern. I 1

Be it known that I, Gnonens LEIGHTON, a citizen of the Republic of France, and residing at Paris, Seine Department,"No. 7

Rue Thorel, in the Republic of France, have invented certain new and useful Improvements in the Manufacture of Drawing Tacks, of which the following is a specification.

This invention relates to improvements in the manufacture of drawing tacks of the class in which the point is formed integral with the head by the process of cutting out the same in the head and bending at a right angle. The said improvements confer upon the point and particularly at its base a much greater strength than is afforded in known devicesywherebythe sameis not subject to bending or breakage when the drawing tack is inserted into the board or withdrawn therefrom.

The following description, together with the accompanying drawings which are given by way of example, sets forth an embodiment of this invention, wherein:

Fig. 1 is a plan view of a portionof the steel band out of which a triangular portion is cut and then bent in order to form a point. Fig. 2 is a plan view of the same portion after being subjected to a pressing action which serves to strengthen the base of the point. Fig. 3 is a cross-section on the line 33, Fig. 2. Fig. 4 is an elevational view showing the point after the first.

lateral compression. Fig. 5 is a cross-sec tion on the line 5-5, Fig. 4. F ig. 6 is a front view of the said point'after the second compression. Fig. 7 is a cros'ssection on the line 77, Fig. (3. Fig. 8 is a front view of the point after the third compression. Fig. 9 is a cross-section on the line 99, Fig. 8. Fig. 10 is a plan view of the drawing tack in the finished'state. Figs. 11, 12

I and 13 show respectively in front and side elevation and in plan viewed from below, a

tool for pressing the said drawing tack. V

The operation comprises the cutting of the triangular portion a in a steel band I), Fig.

1, and the pressing of edges of the aperture 0 for example by means of a tool as shown in Figs. 11 to 13. By comparison of Figures 1 and 2 it is observe-d that the pressing operation brings together the edges of the aperture in such'manner that the latter is almost entirely closed. The edges thus driven forward will constitute supports at the base of the point which will prevent the v latter from being bent down towards the aperture. ,1

flhedie (Z which is shownin Figs. 11 to 13 comprises a diametral slot d and a radial slot (5 perpendicular thereto, forming two segments (5 and d whose section is thatof a quarter circle and which pro ects outwardly of the remainder of the tool in order to perform the stamping operation. After the point has been definitely formed, the head 6 of the drawing tack, which has usually a circular shape, is cut out of the band 6 by a suitable die.

These segments are convex and inclined towards the center, they act by pressure upon the metal and jump the same, as shown in Figures 2 and 3. 1n virtue of the resiliency of the branches d*, d resulting from the slots 0Z (Z and on account of the inclination of the working faces, the latter tend to slide over' the metal in slightly approaching each other and in causing the metal to shift a little so as to close the slot 0 and form small ribs upon the edges of the latter.

Thisinvention is applicable irrespectively of the configuration which is to be subsequently, given to the point. In the example shown, the point is laterally compressed by repeated operations as shown in Figs. 4; to 10, whereby it is caused to assume the form of a pyramid with concave sides. This shape provides a great rigidity as well as cutting edges which are adapted to penetrate into the wood with facility and to adhere strongly to the same.

Claims:

1. In a process for the manufacture of drawing tacks, consisting in cutting out a point from a sheet metal band, in raising this point atright angle, in stamping the edges of the opening so as to cause them to i approach each other, in shaping the point and in cutting the circular headof the tack so as to separate the same from the band, the step of causing the edges of the aperture to approach each other close to the base of the point and of shaping the point so that 4 approach each'other, in shaping the point and in cutting the circular head of the tack so as to separate the same from the band, the step of causing the edges ofthe aperture to approach each other close'to'th'e base of thepoint and of shaping the point in the form of a pyramid the base of which will bear upon the said edges of theaperture which have been brought close to each other. 3. drawing tack the :point of which is "out ohtfro'nithe head and raised at right angle upon the latter, the edges of the aperture being contiguous to each otherand the point having the shape of a triangular pyramid and its base extending partially over the contiguous edges ofthe aperture so as to hear upon then. 7 a i. A drawing tackthe point of which is cut out froin the head and raised at right angle upon'the latter, the edges of the apertureheing contiguous to each other and the point having the shape of atriangular pyramidwith concaue, sides and cutting edges and the base of which extends partially over the contiguous edges of the aperture so as to bear upon them,

a 3 GEORGES LEIGHTON.

I clalm the foregoing 

